[MR staging in renal neoplasms. Comparison with surgical data]

Forty-six patients bearing renal lesions were studied with magnetic resonance (MR) imaging. A superconductive magnet (1.5 T) was used to stage the lesions according to Robson's criteria. A positive correlation between MR and pathologic results was observed in 40 cases. MR imaging overstaged 4 lesions: 2 of them for suspected infiltration of perirenal fat (MR stage II, versus pathologic stage I), one was a false-positive finding for lymph node metastasis (MR stage IIIb, versus pathologic stage II) and another one for suspected bowel loop infiltration (MR stage IVa, versus pathologic stage II). Two lesions were understaged: in one case bowel loop infiltration was missed by MR imaging (MR stage II, versus pathologic stage IVa) and another one for a false-negative lymph node metastasis (MR stage II, versus pathologic stage IIIb). In all the cases with involvement of renal vein and vena cava, MR imaging correctly demonstrated the presence of neoplastic thrombi.